Why do you assume that the small sample of players you have played against are representative of the entire population? It doesn't appear that way in the match play games you have played where you're only 4-8 against the Masters.
This is the internet and this is a video game. Expecting a high level of integrity and ethics is a bit much. Perhaps you're a video game purist. Just realize, yes, random people will quit in random multiplayer stroke play games.........so simply don't play those so much.
Like Marioh stated, its very easy to scope out posers by looking at their stats.
And if you think I'm paper-mache and you'll steam right through me, again you're welcome to break off some credits for a MPC.